Flame blocking liner materials

ABSTRACT

A fire blocking non-woven needlepunched textile structure, comprising a first fiber component containing polyacrylonitrile copolymer with a halogen containing monomer and a second fiber component. The second fiber component is selected such that it supports the first fiber component during burning, optionally including an inorganic filler as a coating for the first and second fiber components. In alternative embodiment, the present invention provides a fire blocking non-woven textile structure containing the above first and second fiber components, blended with a third binder fiber component in the form of a vertically lapped nonwoven structure.

FIELD OF THE INVENTION

[0001] This invention relates to fire resistant needle punched materials and to their methods of preparation. The invention has particular utility in the formation of fire blocking fabric as a liner under upholstery fabric and mattress ticking. The invention also has utility for the production of fire resistant vertical lapped batting material.

BACKGROUND OF THE INVENTION

[0002] As noted in U.S. Pat. No. 6,287,690, it is well known in the textile industry to produce fire resistant fabrics for use as upholstery, mattress ticking, panel fabric, etc., using yarn formed of natural or synthetic fibers, and then treating the fabric with fire retardant chemicals. Conventional fire retarding chemicals include halogen-based and/or phosphorous-based chemicals. Such treated fabrics reportedly are heavier than similar types of non-fire retardant fabrics, and are said to have a more limited wear life.

[0003] Not surprisingly, therefore, one can uncover numerous disclosures aimed at modifying the burning characteristics of fiber materials. For example, in U.S. Pat. No. 4,600,606 a method of flame retarding textile and related fibrous materials is reported, which relies upon the use of a water-insoluble, non-phosphorous containing brominated aromatic or cycloaliphatic compounds along with a metal oxide. U.S. Pat. No. 4,026,808 reports on the use of a phosphorous containing N-hydroxy-methyl amide and tetrakis(hydroxymethyl) phosphonium chloride. U.S. Pat. No. 3,955,032 confirms the use of chlorinated-cyclopentadieno compounds, chlorobrominated-cyclpentadieno compounds, either alone or in combination with metal oxides.

[0004] U.S. Pat. No. 4,702,861 describes a flame retardant composition for application as an aqueous working dispersion onto surfaces of combustible materials. Upon exposure to elevated temperatures and/or flame, the formulation reportedly creates a substantially continuous protective film generally encapsulating and/or enveloping the surface of the article onto which it is applied. The film-forming materials are based upon an aqueous latex dispersion of polyvinylchloride-acrylic copolymer together with certain other film-forming and viscosity controlling components.

[0005] Other disclosures which offer additional background information include U.S. Pat. No. 4,776,854 entitled “Method for Flameproofing Cellulosic Fibrous Materials”; U.S. Pat. No. 5,051,111 entitled “Fibrous Material”; 5,569,528 entitled “Treating Agent for Cellulosic Textile Material and Process for Treating Cellulosic Textile Material”; and U.S. Pat. No. 6,309,565 entitled “Formaldehyde-Free Flame Retardant Treatment for Cellulose-Containing Materials”.

[0006] It is also worth mentioning that within the various efforts to provide flame resistant fabric products, various polymers themselves have emerged as substrates for use as flame resistant fibers. For example, melamine and melamine/formaldehyde based resinous fibers are said to display desirable heat stability, solvent resistance, low flammability and high-wear characteristics. One form of melamine/formaldehyde fiber is marketed under the tradename Basofil™. In addition, the aromatic polyamide family or aramids reportedly have high strength, toughness, and thermal stability. Aramid fibers are marketed under the tradenames Nomex™ and Kevlar™.

[0007] Furthermore, acrylic fibers are well-known in the synthetic fiber and fabric industries, as are the modified acrylic fibers (modacrylic). Such modacrylics are relatively inexpensive, and have been used in various blends with the fibers noted above to provide fire-resistant fabric material. One particular modacrylic fiber is sold under the tradename Protex™, which is available from Kaneka Corporation, Japan.

[0008] In addition, flame retardant viscose fibers have become available, and one particular viscose fiber is sold under the tradename Visil™. More specifically, Visil™ is said to comprise a silicic acid containing viscose, with a limiting oxygen index (i.e., the minimum concentration of oxygen necessary to support combustion) in the range of 0.27-0.35, depending upon a particular textile construction.

[0009] Finally, it is worth noting that various manufacturers have produced and sold fireresistant fabric material. They are as follows: 1. E.R. Carpenter's “Fire Stop™”, which relies upon Basofil™/modacrylic high loft batting; 2. Chiquola Industrial Fabric's “FireGuard™” which relies upon core spun flame retardant yarns into woven or knit form; 3. ChemTick Coated Fabrics “Flame Safe™” which relies upon core spun yarn in woven configuration with flame retardant treatment; 4. Elk Corporation's “VersaShield™” which relies upon a woven fiberglass base with a soft foam like coating on one side; 5. Jones Fiber Products, Inc.'s “T-Bond™” which relates to a flame retardant treatment of cotton batting; 6. Legett & Platt's “Pyro-Gon™” which is a batting of a blend of Pyron (panox) fibers with other fibers; 7. MLM, LLC's “Allesandra” which is a core spun flame retardant yarn in woven form; 8. Tex Tech's various blends of Basofil™ and Nomex™, Kevlarm and PBI in the form of needlepunched felts; and 9. Ventex's “Integrity 30™”, SpunGold™ and AKTIV™ which collectively relate to various products of knits and nonwoven battings that may include Basofil™, panox, Kevlarm or Nomex™.

[0010] It is therefore an object of the present invention to expand upon the technology directed at the manufacture of flame retardant materials, and develop a fire resistant needle punched material that can serve, among other things, as a protective liner material. More specifically, it is an object of the present invention to develop new types of needle punched materials that rely upon a foundation component of a modified acrylic type fiber that is based upon a copolymer of polyacrylonitrile and a halogen based monomer to provide an inexpensive fire blocking composition.

[0011] It is also an object of the present invention to provide a fire-resistant material which relies upon a needle punched non-woven manufacture of two principal components, wherein one component is selected to provide non-burning characteristics, and a second component is selected to support and maintain the first component in place during burning as well as to provide non-burning characteristics, thereby resulting in a synergistic composition that reduces the burn rate in a given liner application.

SUMMARY OF THE INVENTION

[0012] In a first embodiment, the present invention comprises a fire blocking non-woven needlepunched textile structure, comprising a first fiber component containing polyacrylonitrile copolymer with a halogen containing monomer and a second fiber component, wherein said second fiber component supports said first fiber component during burning, optionally including inorganic filler as a coating for said first and second fiber components.

[0013] In a second embodiment, the invention herein comprises a fire blocking non-woven textile structure, in the form of vertical lapped batting, comprising a first fiber component containing polyacrylonitrile copolymer with a halogen containing monomer and a second fiber component, wherein said second fiber component comprises a viscose fiber containing silicic acid and/or a melamine-formaldehyde polymer, and a third fiber component comprising a binder fiber having the capability to melt bond said first and second components wherein said first and second components are melt bonded together by said binder fiber.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] In the first embodiment, the fire resistant non-woven material of the present invention, which can be used as a protective liner material, is preferably manufactured from a needle-punched combination of modacrylic fiber with a second fiber component which may comprise a viscose fiber containing silicic acid and or a melamine/formaldehyde polymer. Optionally, and as described in more detail below, an inorganic filler such as vermiculate may be included as a coating. Other inorganic fillers include those selected from the group consisting of graphite, fumed silica or silica dioxide, or titanium dioxide, and mixtures thereof.

[0015] It should be noted that at least one factor contributing to the performance of this first embodiment, as a unique fire resistant non-woven material, is the modacrylic fiber. When the modacrylic is activated by heat, it apparently assists in the displacement of oxygen thereby reducing heat release and burn rate. Furthermore, the vermiculate coating may then serve to disperse the heat across the needlepunch fabric. However, the invention herein is not limited to any particular theorized functionality of the individual components and relies upon the various combinations that are ultimately described in the appended claims.

[0016] The modacrylic fiber is preferably based upon a polyacrylonitrile copolymer with a halogen containing comonomer, and the halogen containing comonomer is preferably poly(vinyl chloride) or poly(vinylidine chloride). A preferred modacrylic fiber is available form Kaneka Corporation, under the tradename Protex™. In a most preferred embodiment, the modacrylic employed herein is sold under the tradename Protex™ M, at a specific gravity of 1.45-1.60 with a fiber denier of 2.2 dtex×38 mm. Protex™ M is described as having the following chemical components: acrylonitrile, vinylidine chloride copolymer, antimony oxide. A preferred viscose fiber containing silicic acid is sold under the tradename Visil™, available from Sateri Oy Inc. The Visil fiber is type AP 33 3.5 dtex×50 mm. It is composed of 65-75% regenerated cellulose, 25-35% silicic acid, and 2-5% aluminum hydroxide. A preferred melamine/formaldehyde fiber component is sold under the tradename Basofil™, available from McKinnon-Land-Moran, LLC.

[0017] Preferably, the non-woven material will also have a basis weight of 100-500 g/m², including all increments therebetween at 1 g/m² variation.

[0018] The above referenced fire blocking non-woven textile therefore may preferably contain the modacrylic polymer component (e.g., polyacrylonitrile copolymer with poly(vinylidine chloride)) at levels of about 50-80% (wt.), and correspondingly, the second fiber component which supports the modacrylic component may be present at about 20-50% (wt.). In a particularly preferred embodiment, the modacrylic component is present at about 80% (wt.) and the second fiber component is preferably a viscose fiber containing silicic acid and/or a melamine/formaldehyde polymer which is present at about 20% (wt.). In the context of all of these preferred ranges, it should be understood that within the broad scope of this invention, all increments therebetween are included, at 1% (wt) variation.

[0019] While not being bound by any particular theory, it has been observed that in the context of the above needle punched non-woven structure, the second fiber component serves to support the first fiber component during burning. By “support” it is meant that the second fiber maintains the first fiber component in place thereby reducing the tendency of the first fiber component to undergo shrinkage during burning, which shrinkage will sacrifice considerably the fire blocking performance. Accordingly, the combination of the first and second fiber components, through the needle punching operation, allows for the development of an relatively inexpensive fire blocking composition which can be readily applied as a fire blocking fabric liner under upholstery fabric and mattress ticking, thereby protecting the more flammable interior components of such products from igniting and participating in the burning process.

[0020] In addition, and again, without being bound by any particular theory of operation, it is also believed that the selective use of the modacrylic fibers herein, that preferably rely upon a copolymer of polyacrylonitrile and a poly(vinylidine chloride) copolymer structure, releases hydrochloric gas during the burning process. It is believed that the hydrochloric gas then assists in controlling the burn rate, providing another overall synergistic feature with respect to the above disclosed strategic selection of the individual components. Also, when combustion temperatures exceed 600° F., oxyhalides are formed which take up the free radicals formed in the vapor phase.

[0021] Furthermore, as noted above, it is preferable that the above non-woven include an inorganic filler, e.g. vermiculite as a coating component. Vermiculate is reference to one of the mica groups that are used as granular fillers, and comprise a crystalline layer silicate material. However, some of the silicon atoms are replaced with aluminum, producing a negative charge that is neutralized by the interlayer cations, mostly magnesium. The vermiculite particles are of a planer structure consisting of platelets that have a minimum 400:1 xy plane to z plane ratio. Preferably, the level of vermiculate herein, as a coating in the non-woven, is about 20-40 g/m², including all increments therebetween at 1.0 g/m² variation.

[0022] In accordance with the above embodiment, the fire blocking non-woven material is preferably of a thickness of: 1.5-25 mm, including all increments therebetween at 1.0 mm variation.

[0023] In a second preferred embodiment, the above non-woven textile is further modified, in the sense that the concentration of the first and second fiber components are reduced in favor of the use of a binder polymer fiber. Such binder polymer fiber has the capability to melt bond with the first and second fiber components. The preferred binder fiber is 4d×2″ from either Nan Ya or Sam Yang in Korea with the outer layer having a melting point of 150° C. which melting point is lower than the melting point of the inner layer of this particular binder fiber material. Furthermore, in this embodiment the first component modacrylic fiber is first blended with the second fiber component (viscose fiber containing silicic acid and/or melamine/formaldehyde polymer) as well as the bicomponent polymer fiber noted above. The three fibers are blended together, formed into a web which is then vertically lapped and then bonded in a hot air oven as the final process. The binder fiber outer layer melts and flows onto the other fibers which bonds the structure together.

[0024] Elaborating upon the above, and in the broad context of the present invention, the binder fibers of the present invention may include one or plurality of polymer components. In addition, the binder fiber may be in the form of a sheath/core, side by side, or monofiliment configuration.

[0025] In accordance with the above, the modacrylic fiber component is present at a level of about 50-70% (wt.), the second fiber component is present at a level of about 10-20% (wt.) and the binder fiber is present at a level of about 10-30% (wt.). Again, as noted above, in should be understood that in the context of the present invention, all increments therebetween are included at 1% (wt) variation. Furthermore, such composition preferably is prepared at a basis weight of 100-500 g/m², and at all 1.0 g/m² increments.

[0026] While the invention has been described in detail with reference to specific preferred embodiments, it will be appreciated that various changes and modifications can be made, and equivalents employed, without departing from the scope of the following claims. 

What is claimed is:
 1. A fire blocking non-woven needle-punched textile structure, comprising a first fiber component containing polyacrylonitrile copolymer with a halogen containing monomer and a second fiber component, wherein said second fiber component supports said first fiber component during burning, optionally including an inorganic filler as a coating for said first and second fiber components.
 2. The fire blocking non-woven textile structure of claim 1, wherein said second fiber component is selected from a viscose fiber containing silicic acid and/or a melamine/formaldehyde polymer.
 3. The fire blocking non-woven textile structure of claim 1, wherein said halogen containing monomer is poly(vinyl chloride) and/or poly(vinylidine chloride).
 4. The fire blocking non-woven textile structure of claim 1, wherein said polyacrylonitrile copolymer contains Sb₂O₃.
 5. The fire blocking non-woven textile structure of claim 1 wherein said polyacrylonitrile copolymer is present at a level of 50-80% (wt).
 6. The fire blocking non-woven textile structure of claim 1 wherein said textile has a basis weight of 100-500 g/m².
 7. The fire blocking non-woven textile structure of claim 1 wherein said vermiculate is present at a level of about 20-40 g/m².
 8. The fire blocking non-woven textile structure of claim 1 wherein the inorganic filler is selected from the group consisting of vermiculate, graphite, fumed silica or silica dioxide, or titanium dioxide.
 9. A fire blocking non-woven textile structure, in the form of vertical lapped batting, comprising a first fiber component containing polyacrylonitrile copolymer with a halogen containing monomer and a second fiber component, wherein said second fiber component comprises a viscose fiber containing silicic acid and/or a melamine-formaldehyde polymer, and a third fiber component comprising a binder fiber having the capability to melt bond the other fibers in the nonwoven structure and wherein said first and second components are melt bonded together by said binder fiber.
 10. The fire blocking material of claim 9 wherein said polyacrylonitrile copolymer is present at a level of about 50-70% (wt.), said second fiber component is present at a level of about 10-20% (wt.) and said binder fiber is present at a level of about 15-30% (wt.).
 11. The fire blocking material of claim 10 wherein said polyacrylonitrile copolymer is present at a level of about 60-65% (wt.), said second fiber component is present at a level of about 15-20% (wt.) and said binder fiber is present at a level of about 15-25% (wt.).
 12. The fire blocking material of claim 9 wherein said textile has a basis weight of 100-500 g/m².
 13. The fire blocking material of claim 9 wherein said binder fiber comprises one or a plurality of polymer components.
 14. The fire blocking material of claim 9 wherein said binder fiber comprises a sheath/core, side by side, or monofiliment configuration. 